A participant to a conference held over a network may be interrupted, i.e., pulled out of real-time listening or participation, for a variety of reasons. For example, the participant may need to step away from the conference to answer another call, or briefly discuss a matter of immediate urgency with a co-worker. Alternatively, the participant may invoke some feature of the conference service that results in the conference audio being interrupted, such as playing out the roster, receiving whisper information, moving to a sidebar conversation, etc. Upon returning to the live conference the participant usually wants to listen to what transpired in the conference during the time he was gone. Simply listening to a recording of the missed portions of the conference, however, is inadequate insomuch as the participant is permanently shifted away from real-time participation.
A number of prior art conferencing systems include a feature that allows portions of a conference session to be recorded and then played back at an accelerated rate, in what is commonly referred to as “catch-up” mode. The problem with these systems is that the participant frequently forgets that he is listening to the conference in catch-up mode, and attempts to speak as a participant in the conference. Comments made during catch-up mode, however, cannot be mixed into the real-time (“live”) conference because the live conference has already progressed beyond the point in time of the catch-up mode playback.